Sex determination in Mexican-beaded lizard specimens (Heloderma alvarezi and Heloderma horridum) employing contrast radiography method

Background: Alternatives to gross external anatomical sex determination are often required, peculiarly in species displaying poor or absent gross sexual dimorphism, such as the beaded lizard. This study evaluates results of hemipenile contrast radiography accuracy as compared to ultrasonography of the same beaded lizard (Heloderma alvarezi and Heloderma horridum). Methods: Eleven captive adult beaded lizards (4 H. alvarezi and 7 H. horridum), underwent hemipenis contrast radiography, and results compared with coelomic ultrasound. Results: By ultrasound, 2 lizards were females and 9 were males. By contrast hemipenis radiography, 2 animals were females and 9 were males. In this sample, there was a Kappa concordance of 1. Conclusions and clinical relevance: In this species, contrast hemipenis radiography proved to be a reliable diagnostic tool for hemipenes identification, and sex determination with all test specimens. Further studies including a larger number of animals and different lizard species are warranted.